Fan



Feb. 18,1936. A. G. LANGENKAMP Er AL 2,030,993

FAN

Filed Aug. 27, 1934 5 Sheets-Sheet 1 ATTRNEYS Feb. 18, 1936. i A. G. LANGNKAMP ET Al. i 2,030,993

FAN

Filed Aug; 27, 1954 s sheets-sheet 5 Feb. 18, 1936. A. G. LANGENKAMP ET A1. 2,030,993

FAN

Filed Aug. 27, 1934 5 sheets-sheet "4 Feb. 18, 17936. A. G. LANGENKAMP Er AL 2,030,993

` 4FAN Filed Aug. 2.7,4 1934 5 Sheets-Sheet l5 l l/VVE/VT/PS ALBERT e. Adam/MMP y Hoy H. Mea/Pay.

Patented Feb. 18, 1936 vUNITED STATES FAN Albert G. Langenkamp and Roy 11./` McElroy,

Dayton, Ohio, assgnors to International Eng-lneering, Inc., Dayton, Ohio, a corporation of Ohl Application August 27, 1934, Serial No. 741,552

. 8 Claims.

This invention relates to fans and, in particular, to such fans as are used for Ventilating, exhaust or cooling purposes.

One object of our invention is to provide a fan unit having means for reducing the backward circulation of air near the tips ofthe blades.

Another object is to provide such a fan'unit wherein the air which attempts to circulate backwardly at the tips of the blades is forced to follow a circuitous path, which results in the reduc-- tion of this eil'ect to a much smaller amount than has hitherto been obtainable.

Another object is to provide a fan unit having such means for preventing the backward ilow of air near the blade tips, combined with a Ven-` turi type of intake passageway: this combination increase the eiiciency of the fan unit.

Another object is to provide a fan unit of the above description, wherein the main fan blades 2o are assisted by auxiliary or stub blades situated between the main fan blades, and of a smaller extent inwardly than the latter.

' Another object is to provide a multi-blade fan having a rim interconnecting the tips of the blades, and a frame encircling this rim,the frame having a iianged portion so arranged that the adjacent edges of the inner surfaces ofthe rim and the frame portion are substantially flush with one another.

Another object is to provide a fan unit with a central deilector hub which is approximately the size of the motor, this deilector hub increasing the static resistance and preventing the rebounding air, from remaining at the center of the fan or passing through the motor, the eiciency of the fan being low at its center.

Another object is to provide a deector hub of the nature just described, wherein the de- 4 ector hub is of convex conguration whereby to deect air rebounding from obstacles in the path thereof, this air being thereby directed tof ward the tips of the fan blades where the efciency is higher than at the center.

45 Another object is to provide a deector hub of the above description wherein the fan blades are carried inwardly to points upon the hub, thereby assisting in keeping the air turbulent at the center of the fan and preventing lthe dead vacuum 50 space which would otherwise tend to form.

Another object is to provide a fan unit assembly mounted upon a substantially annular support, this support being attachable by itself toa circular Opening, or combinable with a square 55 cover plate to iit a square opening, the same fan (Cl. IWL-168) unit being applicable to both installations merely by attaching it to the square border member.

- Another object is to provide a fan unit assembly of the type described immediately above, wherein the square border member, to winch the annular fan unit support is attachable, is provided with louvres adapted to open and close according to whether the fan is in operation or idle.

vIn the drawings:

Figure 1 is 'a side elevation, partly in vertical 10 section, of one embodiment of the fan unit of our invention;

Figure 2 is an elevational view of the fan unit shown in Figure 1, looking toward the intake side of the fan; 1

Figure 3 is a view similar .to Figure 2, but looking toward the discharge side of the fan;

Figure 4 is a view of a modified form of fan 'unit similar to that shown in Figure 3, but additionally provided with auxiliary fan blades to 20 assist the action of the fan blades;

Figure 5 is a fragmentary section showing the tip and support construction of a modied form of fan unit;

Figure 6 is a view similar to Figure 5, but of 25 another modified form' of fan unit;

Figure 'lis a View similar to Figures 5 and 6, but of still another modiiied form of fan unit;

Figure 8 is an elevational view of the fan unit show in Figure 2, as attached to a square border 30 member adapted to t al square opening in a wall;

Figure 9 is a view similar to the assembly shown in Figure 8, the square border member being additionally provided with louvres; 35

Figure 10 is a section through the fan blade takenon-the line lll-Ivof Figure 3;

Figure 11 is a section through the fan blade taken on the line ll-ll of Figure 3.

Referring to the drawings in detail, Figures 1, 2 and 3 show the fan unit of our invention in its preferred embodiment. 'I'his fan unit consists, in general, of a fan unit support, generally designated I; a bracket member, generally designated 2; a motor, generally designated 3, and a fan, 45 generally designated a. y

The ,fan unit support l consists of an annular member having a roughly conical and inwardly extending mouth surface 5 of suitable configuration to provide an intake passage for the air drawn in by the fan i. The configuration of the surface 5 is preferably of the so-called Venturi type, a curvature being imparted thereto, this curvature being of such a nature as to emciently direct the air toward the fan blades. It will be understood,

Immediately beyond the intake portion 5 of the support member, the latter is provided with an offset or shouldered portion 6 having a reverselydirected groove 1 and a side wall 8. The support member I is preferably made with hollow portions 9, between which are arranged strengthening portions II! and web portions II adapted to receive theends of the bracket 2 (Figure 3). The web portions II are provided, for this purpose, with the threaded holes I2, the latter being adapted to receive the cap screws I3, by which the bracket 2 is attached to the support member I. Thus the support member I on the discharge side of the fan unit has outer and inner ridges I4 and I5,

separated from one another by the hollow portions 9 and by the strengthening members I 0 and web portions II.

The bracket 2 (Figure 2) is of roughtly Y- shaped form and is provided with a base portion I6 near the junction of its arms. This base portion serves to support the motor 3 by means of the projections I1 Vfrom the latter, and by the cap screws I8 forming the connection therebetween.

The motor 3 is provided with a drive shaft 2U' upon which the fan 4 is mounted.

The fan 4 is provided, for this purpose, with a. central bore 2| in which the motor shaft 26 is secured, as by the set screw 22.` The fan 4 is provided with a hub 23 having a diameter substantially equal to that of the motor 3. The external surface 24 of the hub 23 isv convex, it`being adapted to deet air toward the blade tips of the fan 4 when such air rebounds from obstacles in line with the fan unit.

The fan 4 is provided with blades 25 attached at their inner ends to the hub 23 and at their outer ends to the fan rim 26, these blades being preferably of streamlined cross section. The fan blades 25 are extended inwardly over the hub 23, as at 21, in order to provide for increased turbulence of the air at the center of the fan and thus to relieve the tendency of a vacuum forming at that point. The inner surface 28 of the fan rim 26 is substantially in line with the edge of the Venturi intake portion 5 at its backward edge. The outer surfaces 29 of the fan rim 26 lies behi'nd the annularshoulder 6 of the support member I, and adjacent to the annular inner side wall 6 of the support member I. Accordingly, any air tending 'to return to the forward side of the fan blades around the rim 26 of the fan must pass through the space between the surfaces 8 and 29 (Figure l) and pursue a circuitous path between the forward edge of the fan rim 26 and the shouldered portion 6 on the support member I. This feature effectively reduces the inefficiency of the fan ordinarily caused by the back-wash of the air around the tips of the blades and substantially forms a seal.

In the modified form of fan unit shown in Figure 4, the fan 4 is provided with auxiliary or stub blades 36 extending inwardly from the rim 26 and providing assistance for the main fan blades 25. In this manner the efficiency of the fan is considerably increased. Theseauxlliary blades 36 are likewise preferably of streamlinedi cross section. The construction of the fan unit shown in Figure 4 is otherwisel substantially the same as that shown in Figures 1 to 3 inclusive.

In Figure 5 is shown a modified form of fan unit construction, the support vmember 35 having anged portions 36v and 31 arranged substantially at right angles to one another. The support member 35 is also provided with a baille ring 38 which serves to provide a similar circuitous path for the air tending to return past the tips of the fan blades, as was described in connection with Figures 1 to 3 inclusive. In this respect, the presence of. the baille ring 38 serves somewhat the' same purpose as the shouldered portion 6 in Figure 1, but the action of the fan is somewhat different in the absence of the Venturi type intake passageway 5. The flanged portion 36 is substantially concentric with the fan rim 26, whereas the flanged portion 31 serves as a means of attaching the fan unit to the building wall 39, as by the bolts 40. Instead of the wall 39 being attached directly to the flange 31, a square border member may be interposed as is described below in connection with Figures l to 3 inclusive.

A modied form of fan unit construction shown in Figure 6 is similar to that described in connection with Figure 5. In Figure 6, however, the battle ring 4I is similar to the baille ring 38, but is placed on the opposite side of the fan rim 26.

In the modified form of fan unit shown in Figure '1, the construction is similar to that shown in Figures 5 and 6, but the flanged portion 36 is provided with baiile rings 42 and 43 arranged on both sides of the fan rim 26. By this construction the air tending to return past the tips of the blades must pursue a still more circuitous path than in the constructions previously described.

The fan unit shown in Figures l to 3 inclusive is directly adaptable and attachable to a circular opening in a wall, merely by using bolts in place of the cap screws I3. The same bolts can serve to connect the fan unit to the wall, as connect the bracket 2 to the support I. In practice it is frequently found that square openings are more convenient to form in walls, or else are already present in the building.

To obviate the necessity of carrying fan units in stock, which consist of two different types, one having a square support member and the other having an annular or circular support member I, we provide a border member 5D, as shown in Figures 8 and 9. This border member 50 is provided with a circular inner aperture 5I and a square outer edge 52, the whole being strengthened by webs 53 running diagonally inward from the corners. The webs 53 are provided with bosses 54 which serve to receive holes 55 for the attachment of the border member to the wall. In

shutter 62 rests against the shutter rod immeat rest, the free edge of each diately beneath it, so that the aperture is effectively closed. When the fan starts operation, however, the louvers or shutters 62 open, allowing the air to escape between the successive shutters.

By thus providing a fan unit having a fan`rim `'imi1ttnkea f1ywhee1 and running in a slot or offset in the fan support or frame, we have succeeded in substantially eliminating the back-wash or 'countercirculation at the blade tips, this conoperate with one another to give an eiiiciency struction virtually forming an air seal between the fan rim and its supporting frame. At. the same time, by our provision of the hub portion, substantiallyth'e size of the motor, we have substantially reduced the loss in efciency by the backward ow of air toward the fan center, this effect being enhanced by the inward extension of the fan blades over the hub portion. By the further provision of the Venturi type supportand-intake-passage, we have increased the eiciency'to a still further extent, these features cowhich has hitherto not been attainable in such fans, and resulting in a larger discharge of air in cubic feet per minute for a given size of fan. Our provision of the auxiliary blades aids still fiu'ther in raising this eiilciency. Finally we have provided a fan unit which may'be carried in stock and applied directly to circular apertures, or by means of a border member, to square apertures: this feature eliminates carrying in stock both round and square types of fan units. It will be understood that we desire to coml prehend within our invention such modifications `as may be necessary to adapt it to varying conditions and uses.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A fan unit comprising a multi-blade fan having an annular rim, and a supporting frame having an annular oifset portion adapted to re' ceive said rim, said oisetportion having a reversely-directed groove, the inner surface of said supporting frame being substantially flush with the inner surfaceof said rim, said offset portion being adapted to reduce the backward ow of air around the tips of said blades.

2. A fan unit comprising a multi-blade fan having an annular rim, and a supporting frame having an annular offset portion adapted to receive said rim, said offset portion having. a reversely-directedgroove, the inner surface of said supporting frame being inwardly flared to form an intake passageway whose inner edge is substantially ush with the inner surface of said rim, said offset portion being adapted to reduce the backward ow of air around the tips of said blades and, said inwardly flared intake passageway being adapted to assist the inward flow of air.

3. A 'fan unit comprising a multi-blade fan having an annular rim, and a supporting frame having an annular cut-away portion integral therewith and extending to one edge thereof and adapted to lrotatably receive said rim, said cutaway portion deiining a reversely-directed groove,

the' inner surface of said supporting frame being inwardly flared to provide an intake passageway substantially of Venturi form, the i er surfaceof said rim being substantially co-extensive with said Venturi surface and adapted to facilitate the intake of air to said fan but to reduce the backward flow of air around said rim because of said reversely-directed groove.

4. A fan unit comprising a multi-blade fan having an annular rim, a support, a frame having a groove extending from one edge approximately to the middle thereof and adapted to receive said rim so that one edge thereof is substantially ush with the inner surface of said frame, said groove being adapted to prevent the leakage of air around the tips of said blades and a motor are ranged to drive said fan.

V5. In a fan unit assembly with a multi-blade fan and a. rim therefor, the combination of an annular frame member rotatably receiving said rim, and a rectangular border member having a circular aperture and detachably secured -to said frame member, said border member having louvres mounted thereon but separate from said frame member.

6. In a fan unit assembly with a multi-blade fan and a rim `therefor, the combination of an annular frame member rotatably receiving said rim,`and a rectangular border member havinga circular aperture and detachably secured to said frame member, said border member having louvres pivotally attached thereto and adapted to lclose the aperture thereof when said fan is idle.

7. A fan unit comprising a multi-blade fan', a rim interconnecting the ends of said blades, and a. frame memberencircling said rim b ut spaced apart therefrom, said frame member having an inwardly-extending flange substantially in the mid-plane thereof and adjacent tosaid rim, said ange being integral with said frame and adapted to provide a circuitous path for thebackward passage of air between said rim and said frame member, the adjoining inner ,edgesvof said rim and said frame member being substantially flush with one another, a motor support, arms connecting said motor support to said framev member, and a motor mounted on -said motor support and drivingly connected to said fan.

8. In combination, a Venturi ring, a fan within said Venturi ring having a plurality kof blades, an annular rim on the periphery thereof countersunk in said Venturi ring with its internal surface 

